Agricultural formulation products must be physically and chemically stable for a specified period of time in order to have commercial utility. There are many causes of formulation instabilities, such as active ingredient instability, phase separations (Oswald ripening, crystallization, sedimentations, creamings, etc.) or environmental factors (temperature, humidity/moisture, etc.). In today's agrichemical market, it becomes increasingly common to develop new formulations to contain multiple active ingredients and their required solvents, safeners, and/or adjuvants, etc., in order to achieve the optimal spectrum, efficacy, and delivery efficiency, which consequently makes formulation stability more and more challenging. Therefore, technologies that can effectively isolate, hinder, or eliminate, adverse reactions or interactions between incompatible ingredients are often critical for a successful product.
Cloquintocet mexyl (CQC-M) is a quinoline compound that has the following chemical structure. It functions as an herbicide safener by reducing the phytotoxic
effects of the herbicide on crops to which it is applied. The preparation and action of quinoline safeners has been disclosed in a series of publications such as DE 2546845, U.S. Pat. No. 3,351,525, Chem. Abstr. 79 (1973) 53154r and EP 94 349.
CQC-M will easily convert to its hydrate form upon contact with water as disclosed in WO 02/36566 A1. CQC-M hydrate will then proceed to precipitate as large needles that hinder sprayability and subsequently its ability to function as an herbicide safener. Because of this undesirable hydrate formation, CQC-M is normally formulated as an emulsifiable concentrate (EC) or oil dispersion (OD) where it is dissolved in an organic solvent and thereby isolated from contact with water or as dry formulations such as a wettable powder (WP) or water dispersible granule (WG). Additives may also be included in these formulations to inhibit CQC-M hydrate formation or crystal growth upon dilution of the concentrates or dispersing of the granules into water for spray application as disclosed, for example, in US 2008/0058209 A1 or US 2008/0032890 A1.
Because of the increasing concern over use of organic solvents in agricultural formulations due to their cost, flammability, adverse health effects and contribution to environmental pollution, aqueous formulations have seen increasing use. The oil-in-water emulsion (EW) is one of the most common aqueous formulations used for many agricultural products, where droplets of oil stabilized by surfactant emulsifiers as a discrete phase are uniformly dispersed in water as a continuous phase. However, many stability challenges may exist with these formulations such as when the emulsion is physically unstable and phase separations occur or when oil soluble ingredients are incompatible with ingredients in the aqueous phase. CQC-M dissolved in the dispersed oil phase of an oil-in-water emulsion presents a particular challenge. Preventing contact of CQC-M with water is necessary to prevent CQC-M hydrate formation which will lead to crystal formation, Ostwald ripening and formulation instability. This invention provides a solution to the problem of making stable aqueous formulations containing CQC-M.